1. Field of the Invention
The present invention relates to an immunochromatography method and an immunochromatography kit in which a labeled antibody is used.
2. Description of the Related Art
As a method in which a specific component in a test liquid is measured, there are many immunoassay methods which use an antigen-antibody reaction. In the immunoassay methods, there are many cases in which a non-specific reaction of the antibody or the antigen against the specific component which needs to be measured becomes a problem. Therefore, a method in which the non-specific reaction is suppressed using a blocking agent is commonly used. As methods in which the non-specific reaction is suppressed using a blocking agent, for example, a method of treating a reaction vessel with the blocking agent in the case of an ELISA or a method of treating latex particles with the blocking agent in the case of a latex agglutination method is performed (JP1994-313766A (JP-H06-313766A)). As the blocking agent, bovine serum albumin (hereinafter, abbreviated as BSA), casein, gelatin or the like is used.
Also a method of producing a carrier which suppresses the non-specific reaction using a casein treated with heat at 100° C. for 30 minutes under conditions of pH 7.2 in a system of EIA is disclosed in JP1994-194366A (JP-H06-194366A). Also, a method of suppressing the non-specific reaction by adding casein hydrolyzed to a molecular weight of approximately 1,000 to 26,000 using protease to a reaction solution in which an immunoassay is carried out is disclosed in JP1990-36353A (JP-H02-36353A).
Immunochromatography method is generally often used among immunoassay methods since the operation is simple and a sample can be measured in a short time. As an immune reaction used in immunochromatography method, a competition-type reaction or a sandwich-type reaction is widely used. Of these, in immunochromatography method, the sandwich-type reaction is standard and, in a typical example, the following operation is carried out in order to detect the test substance consisting of an antigen in a sample. First, a chromatographic carrier having a reaction site is prepared by immobilizing fine particles sensitized by an antibody with respect to an antigen which is the test substance on the chromatographic carrier as the solid-phase fine particles, or by directly immobilizing this antibody itself on the chromatographic carrier. Meanwhile, sensitized labeling fine particles are prepared by sensitizing the antibody which can specifically bind to the test substance to labeling fine particles. These sensitized labeling find particles, together with the sample, move chromatographically on the chromatographic carrier. From the above operation, the immobilized antibody becomes the immobilizing reagent in the reaction site formed in the chromatographic carrier and the sensitized labeling fine particles specifically bind to the immobilized sample through the antigen which is the test substance, and as a result, the presence, absence or the amount of the test substance in the sample may be measured by visually determining the presence, absence, or the degree of the signal generated from capturing the sensitized labeling find particles in the reaction site. Also, in immunochromatography method, adding the blocking agent such as protein to a diluted solution of analyte to suppress the non-specific adsorption is generally carried out (JP2004-503248A).